With regard to prototyping GUI's I'd suggest taking a look at https://github.com/mfelleisen/7GUI. https://github.com/Bogdanp/racket-gui-easy could also be a good place to start.
With regard to Racket more generally, I'm probably not the best person to ask since I had a very high friction start where I just banged my head against the wall until things made sense.
With regard to prototyping GUI's I'd suggest taking a look at https://github.com/mfelleisen/7GUI. https://github.com/Bogdanp/racket-gui-easy could also be a good place to start.
With regard to Racket more generally, I'm probably not the best person to ask since I had a very high friction start where I just banged my head against the wall until things made sense.